Sheet metal nail and method of forming same



Feb. 16, 1937.

` 2 Sheets-Shea*l 1 A. B. WlLSON Filed Nov. 1l, 1935 Feb. 16, 1937. A. B. wlLsoN Filed Nov. 11, 1935 -`2 Sheets-Sheet 2 I l 7g.

Patented Feb. 16, 1937 UNITED STATES SHEET METAL NAIL AND NIETHOD F FORMING SAME Allen B. Wilson, Chicago, Ill., a'ssignor to Acme SteelCompany, Chicago, Ill., a corporation of Illinois Application November 11, 1935, Serial No. 49,218

15 Claims.

This invention relates to sheet metal nails and its purpose is to provide an improved nail formed by an improved method from a strip'of sheet metal and adapted to be used for all of the purposes for which ordinary wire nails are ordinarily employed. Heretofore, many efforts have been made to form nails from sheet metal but these attempts have not met with success, due largely to the inability to form a nail which'could be driven into wood or the like without bending or to form one having an adequate head which would withstand Isuccessive blows of a hammer or the like, and which could be withdrawn after being driven, without substantial deformation. 'I11ese difficulties have Abeen overcome in the present invention by providing an improved nail formed of a strip of sheet metal and comprising an improved 'construction of the head and the point of the nail which permit it to be driven without bending and to be withdrawn when desired. A further feature of the invention is the provision of a sheet metal nail of U-shaped cross-section having' an enlarged head and a point which is located on or near the longitudinal axis of the nail so thatY when the nail is driven it retains its original shape and does not deect laterally. A further object of the invention is to provide an improved method of forming sheet metal nails according to which an elongated metal strip is caused to assume a U-shaped cross-section and then cut off into successive sections which are operated upon by dies or the like to form a head at one end of each section and a point at the other end, the point being deflected toward the longitudinal axis of the nail. Still another object of the inventioiisv to prbvide a sheet metal nail comprising an improved head having a plurality of layers of metal extending transversely to the body of the nail. Other objects relate to various features oi construction and arrangement and to details of the'improved method which will appear more fully-hereinafter.

The nature of the invention will be understood from the following specification taken with'the accompanying drawings, in which one embodi-l ment of the improved. nail and one example of the improved method of forming it are illustrated.

ing dies of the apparatus illustrated in Fig. 1 have been operated to cut oi one nail-forming section from the elongated strip shown in Fig. 1;

Fig. 3 is an enlargement Vof the portion of the apparatus illustrated at the right of Fig. 1, 5V showing the relative positions of the parts preliminary to the formation of a head upon one of the nail sections;

Fig. 4 is a section similar to that 0f Fig. 3, but on an enlarged scale, showing the relative posi- 10 tions of the parts after the dies have been operated to form the nail head;

Fig. 5 shows a bottom plan view of the apparatus illustrated in Fig. 1,1 with the lower rolls removed;

Fig. 6 shows a cross-section through the sheet metal strip from which the nails are formed, the

' section being taken on the line -6-6 of Fig. 1;

Fig.- 7 is a sectional view taken on the line 1-1 of Fig. 1, showing portions of the first stage 20 rolls which impartan initial transverse bend to the metal strip;

Fig. v8 is an enlarged section taken onthe line 8-8 of Fig. 1, showing the effect upon the metal strip of the second stage rolls which im- 25 part to the strip a U-shaped cross-section;

Fig. 9 is an enlarged section taken on the line 9-9 oi Fig. 1, showing the action of the clamps which hold the yU-shaped strip while a section thereof is being cut oii to form a nail; 30

Fig. 10 is a sectional view taken on the line Ill-l0 of Fig.. 1, showing on an `enlarged scale the shearing dies which operate to cut oil' a nail section from the source of supply and to impart the desired pointed end structure tothe section; 35

Fig. 11 showsa-n end view of -the completed nail; Y j Fig. 12 shows a side view of the completed nail;- andv Fig. 13 shows a bottom plan view of the eom- 40 pleted nail.

Before describing the method and. apparatus which are employed in forming the improved nail, reference may be had to Figs. 11, 12, and 13, which show the completed nail I5. This nail 45 is of U-shaped cross-section, comprising side walls l5a connected by a curved back wall or top wall |51?. At one end of the nail, the material of these walls is turned outwardly as shown at l5 and then reversely bent as shown at Ira'l to 50 form a head designated generally by the numeral I5. At the other end oi' the nail, the side walls I are sheared off as shown at I5t to form a point' I5, This point may be located in sumantial `alignment. i1-coincidence with the longitudinal 55 axis of the nail by having the back or top wall of the nail curved or bent downwardly as shown at |511. The extent to which the point is deected inwardly toward the axis of the nail will depend upon the size of the nail, thev material of which it is formed and the use to which itis to be put; the deection should be suiiicient to 'overcome the tendency of the nail to bend in the direction of the closed side of the channel and` ywill ordinarily locate the point at ornearthe longitudinal axis of the nail as determined by the center of massof the'cross-section of the nail.

`The nail I is preferably formed from an elongated strip of sheet steel I6 or the like which hasv parallel edges and which is of suillcient width to permit the formation of the completed nail therefrom. rIhis strip I5 is run through a pair of rolls I'I- and I9, shown in Figs. 1 and 7, which have their peripheral surfaces so formed that they turn the side edges of the strip I6 downwardly as shown at I9* and give it a shallow U-shaped cross-section as it passes between them. The strip then passes between two other rolls I9 and 2li, shown in Figs. 1 and 8, which bend the side portions of the strip downwardly to a further extent due to the action of the U-shaped groove I9'l in the upper roll and the corresponding annular projection 2|)n on the lower roll. The' strip I 6 thus acquires parallel side walls I6b which correspond in shape and spaced relation to the side-walls I5! of the completed nail.

. The strip I6 having the U-shaped cross-section imparted thereto by the rolls I9 and 20 is then in readiness to be cut up into sections for the formation of nails I5. The rolls I'I, Il, I9. and 20 are power driven and their ymotion is intermittently arrested so that while the strip I 6 is stationary, it may be gripped by a pair of clamping devices 2| and 22 which have their operating surfaces formed substantially like the peripheral surfaces of the rolls I9 and 25 so that. the upper member 2| embraces the' outside of the strip while the lower gripping member 22 has a projection 22'L which extends up into the groove of the strip. These gripping devices 2| and 22 may be moved toward each other by any suitable operatingmechanism and be caused to gripv the end portion of the U-shaped strip I6, leaving a predetermined part of the strip projecting beyond the faces of the gripping members, as shown in Fig. 3. A head-forming device 23 is then brought into action to form on the end of the strip one of the heads I5 of the completed nail. I 'Ihis head-forming device com- Vprises aplunger 24 which is adapted to be reciprocated horizontally in alignment with the axis of the 'strip II5 and which has slidably mounted thereon a chuck or vsleeve 25.V This sleeve has a circular aperture 2li'l formed therein and this aperture is slidably engaged by the reyduced end portion 24. of the plunger. 'Ihe sleeve 25 has a part 25? of reduced diameter which is slidably `mounted upon the intermediate portion 24b of the plunger and a coil spring. 25

surrounds the parts. 24bjand 25h and extendsl r .between the annular shoulders on the 'body portions of the members 24 and 25 so'that it normally tends to separate them to the extent shown in Fig. 3. The relative movementoi' the members 24 and 25 and y the extent oi'jtheirseparation are limited by a-fpin' 2l which is'fmounted in the .intermediate portion 24"of the' member 24 and which engages a slot 25a yformed in themember' 25. When the members 24 and 25 are thus separated to the maximum extent under the in iluence of the spring 25, the bore 25* of the member 25 is partially occupied by the portion 24 of the plunger, leaving a cavity which is partially occupied by a central projection 24c which is formed on the end of the plunger. The end's'urface of the portion 24n of the plunger is inthe form of an annular groove of curved crosssection as shown at 24d,conforming to the de- 'sired curvature of the portion |5 of the nail head. A

With the parts in the relative positions shown in Fig. 3, the head-forming device 23 is then moved bodily toward the left until the chuck or sleeve 25 engages the end faces of the clamping devices 2| and 22 at which time the extremity of the U-shaped strip I5 will project into the cavity ofthe member 25. Further movement of the plunger 24, with the member 25 held stationary by the clamping devices, with a resulting compression-of the spring 25, will cause the projection 24c to enter the groove of the strip I6 until the extremity of this strip engages the annular end face 24d of the plunger. 'Ihis curved end face then causes the metal ofthe end of the strip to be turned outwardly and this outward movement of the metal continues until it engages the wall of the bore 25.*. By this time, the relative movement of the partv 24* of the plunger with respect to the body 25 of thechuck or sleeve will have proceeded to a point where further continued relative movement will cause the edge of the out-turned part 'of the metal strip to engage the faces of the clamping members 2| and 22 so that the metal will then be turned inwardly and will continue to move inwardly until its edge engages the body portion of the' U-shaped strip. During this time, the projection 24e of the plunger will enter the notch 22h which is formed in the lower 'clamping member 22 and when the plunger 24 has reached the limit of its movement, the parts will bein the .relative positions shown in Fig. 4 and the double flanged head I5e will have been formed on the end-of the strip. The headforming device 23 is then withdrawn, the clamping devices 2| and 22 are released from the strip and the strip is again advanced by-the intermittent rotation of the rolls a distance substantially u equal to the length of the finished nail.

Having formed thefhead on the end of the elongated strip and having advanced the strip through the grippingl devices 2| and 22, these gripping devices are again brought into position to hold the strip and the projecting portion of the strip is then out oi! adjacent to the gripping devices by the action of cutting or shearing dies 29k and 30 which vare shown particularly in Figs. 1, 2, and 10. The upperdie 29 has vshaped cutting edges 29' which diverge at an angle corresponding to the'divergence' of the edges I5t at the point of the finished nail and this upper die also has a transverse cutting edge 29h ist which extends at right angles to the`- axis of the ing die 90 has a `projection 9B* which is adapted to enter the groo edin the under side oi'V the strip beneath the upper.

ie 29 and thereby support the.

strip during the action of the upper die; The lower die" 'also has another projection 3|)b whichl also enters the: groove of the/stripand supports t' clamping member 2| and the end face 2!!c of the upper die, as shown in Fig. 2. The lower die 30 is further provided with a slot 30C which extends downwardly through the body of the die between the parts 3612L and 3l)b and which is adapted to be entered by the V-shaped upper die 29 when the latter moves downwardly to its extreme position. The upper edge of the projection 30B is curved downwardly as shown at 39d ad? jacent to the slot 3l)c with the result that when the upper die 29 is moved downwardly to engage the strip, after the lower die 3U has been moved upwardly to engage and support the strip on its under side, the strip I6 is sheared off transversely by the cutting edge 29b as shown at llic and at the same time the inclined cutting edges 29a of the upper die shear off the side walls of the end portion of the strip-to form diverging surfaces which become the surfaces I5f of the point of the finished nail. As this shearing action takes place, the top or back wall of the extremity of the U-shaped member isdeected downwardly against the curved surface 36d of the lower die, as shown in Fig. 2, to form the point 52 of the completed nail and to cause this point to occupy a position on or near the longitudinal axis of the nail, as explained above. This shearing operation removes a section Id oi' the strip and leaves the completed nail I5. The cutting dies 29 and 39 are then withdrawn and the parts are then in readiness for moving the head-forming device 23 into position to form a head on the body portion of the strip which is then held between the clamping devices 2| and 22, as shown in Fig. 3. In this way, the heads and the points are formed alternately and nails may be quickly formed in succession from the elongated metal strip which has a step by step motion through the apparatus.

Instead of imparting an exact U-shaped crosssection to the strip as it passes through the rollsA of the apparatus, it may be caused to assume a V-shaped cross-section or other equivalent shape, but some form of concave cross-section approximating the U-shaped or its equivalent is desirable becausey of the greater surface of the nail which is exposed to frictional engagement with the wood into which it is driven, as compared with the surface area of wire nails or the like. When the improved nail is driven, the wood enters the groove of the nail in addition to contacting the outer surface thereof so that the total area of contact between the wood and the nail is relatively large and the resistance to withdrawing the nailds correspondingly great. The double flanged head permits the nail to be driven or withdrawn without deformation of the head or other parts of the nail and the V-shaped point having its extremity deiected inwardly toward the longitudinal axis of the nail permits the nail to be driven without bending in any direction. Although various proportions may be successfully employed in practice, it has been foundrfor'exa'mple, that if the sheared edges If of the completed nail make an angle of substantially 17 degrees with the axis of the nail, with the back wall of the nail bent downwardly as shown at |51l for a distance from the end of the nail equal to from one and one-half substantially be constructed in-various forms and that the method may be practiced in various ways coming within the scope of the appended claims.

I claim:

l. A sheet metal nail of angular cross-section having a point deiiected inwardly toward the longitudinal axis of the nail to a sufcient extent to prevent bending of the nail when it is driven.

2. A sheet metal nail of U-shaped cross-section having a point located approximately on the longitudinal axis of the nail.

3. A sheet metal nail of angular cross-section having a flanged head comprising a plurality of layers of metal extending transversely to the longitudinal axis of the nail.

4. A nail comprising a channel-shaped strip of sheet metal having the metal at its end bent outwardly and reversed upon itself transversely to the longitudinal axis of the nail to form a head.

5. A nail comprising a channel-shaped strip of sheet metal having the metal at one end bent outwardly to form a head and having the sides of the channel at the other end cut away along oblique lines to form a point, said point being inclined inwardly toward the longitudinal axis of the nail to a sufficient extent to prevent bending of the nail when it is driven.

6. A sheet metal nail of channel cross-section having the sides of the channel at one end of the nail cut away along converging surfaces to form a point, the back of the channel being deflected to locate said point near the longitudinal axis of the nail.

7. A sheet metal nail of channel shape having its walls bent outwardly transversely to the longitudinal axis of the nail at one end to form a multiple layered head and having said Walls sharpened and deflected at the other end to form a point located inwardly from the outer face of the nail to a sufficient extent to prevent bending of the nail when it is driven.

8. A sheet metal nail of channel shape having its Walls bent outwardly and then reversely bent at one end to form a multiple layered head and having its walls cut away along convergent surfaces at the other end to form a point, said point being deflected to a position substantially on the longitudinal axis of the nail.

9. The method of forming a nail which consists in rolling the edges of an elongated flat strip of sheet metal to form a channel-shaped member, bending the walls of said channel transversely at one end of said member to form a head, and cutting said walls along oblique lines at the other end of said member to form a point.

10. The method of forming a nail which consists in rolling the edges of -an elongated at strip of sheet metal to form a channel-shaped member, bending the Walls of said channel transversely at one end of said member to form a head, cutting said walls along oblique lines at the other end of said member to form a point, and deflecting said point toward the longitudinal axis of the nail.

1l. The method of forming a nail which consists in rolling the edges of an elongated ilat strip of sheet metal to form a channel-shaped member, bendingv the Walls of said channel transversely at one end of said member to form a multi-layered head, and cuttin the Walls of the'other end ofv said member to f rm a point.

12. The method of forming a nail which consists in rolling the edges of an elongated flat strip v one end of said member to form a multi-layered 4Y l ao'ronec head, and cutting and bending said Walls at the other end of said member to form a point located inwardly toward the longitudinal axis of the nail.

13. The method of forming a nail which consists in bending the lateral portions of an elongated iiat strip of sheet metal to form a channel, holding said channel and b'ending the ends ai its walls transversely to form a head, then advancing said channel longitudinally, again holding said channel, and then shearing off said channel to form a pointed end on the head-carrying portion thereof.

14. The method of forming a nail which consists in bending the lateral portions of an elongatedv at strip of sheet metal to form a channel, holding said channel and bending the ends of its walls transversely to form a head, then advancing said channellongitudinally, 'again hold- 'ing said channel, and then shearing on said channel to form a pointed end on the head-carrying portion thereof and to form a transverse end the nail.

` ALLEN B. WILSON. 

